EP0328350A2 — Dry etching with hydrogen bromide or bromine

Claim 1

Independent Claim 112 words

A process for selectively etching a mass, comprising: providing an etching mask over the mass to expose an area of the mass to be etched; and providing a plasma of an etching gas in contact with said mass, said etching gas containing hydrogen bromide, bromine or a combination thereof as a main reactive component that reacts with said mass, whereby said exposed area of said mass is selectivity etched to form said mass having an etched portion and a side wall along a periphery of said etching mask; wherein the temperature imparted to said mass during said etching is set to give the etched mass side wall a predetermined angle of inclination.

Claim 2

Dependent Claim 112 words

A process for selectively etching a mass, comprising: providing an etching mask over the mass to expose an area of the mass to be etched; and providing a plasma of an etching gas in contact with said mass, said etching gas containing hydrogen bromide, bromine or a combination thereof as a main reactive component that reacts with said mass, whereby said exposed area of said mass is selectivity etched to form said mass having an etched portion and a side wall along a periphery of said etching mask; wherein the temperature imparted to said mass during said etching is set to give the etched mass side wall a predetermined angle of inclination.

Claim 3

Dependent Claim 18 words

A process according to claim 1, wherein said mass is made of a silicon or a silicon-containing material.

Claim 4

Dependent Claim 41 words

A process according to claim 1 or 2, wherein said etching is conducted at a temperature of -40° C to + 50° C to form a said side wall of said mass having an inclination angle of less than 90° .

Claim 5

Dependent Claim 41 words

A process according to claim 1 or 2, wherein said etching is conducted at a temperature of 50° C to 150° C to form a said side wall of said mass having an inclination angle of 90° or near 90° .

Claim 6

Dependent Claim 39 words

A process according to claim 1 or 2, wherein said etching is conducted at a temperature of higher than 150° C to form a said side wall of said mass having an inclination angle of more than 90° .

Claim 7

Dependent Claim 27 words

A process according to any preceding claim, wherein said etching gas contains only hydrogen bromide or bromine as the reactive component and further contains an inert gas.

Claim 8

Dependent Claim 72 words

A process according to any preceding claim, wherein the temperature of said mass is chosen for a predetermined inclination angle of said side wall of said etched mass in accordance with the following formula: θ = ½+65 where 0 stands for the inclination angle of the side wall of the etched mass and t stands for the temperature of the mass during etching, the inclination angle 8 having a dispersion of ±5°.

Claim 9

Dependent Claim 35 words

A process according to any preceding claim, wherein said etching gas does not contain a carbon-bearing component, and wherein said etching chamber has no carbon-bearing material in contact with said plasma of the etching gas.

Claim 10

Dependent Claim 98 words

A process for selectively etching a mass, comprising: providing an etching mask over the mass to expose an area of the mass to be etched; and providing a plasma of an etching gas in contact with said mass in an etching chamber, said etching gas containing hydrogen bromide, bromine or a combination thereof as a main reactive component that reacts with said mass, said etching gas not containing a carbon-bearing component, whereby said exposed area of said mass is selectivity etched, wherein said etching chamber has no carbon-bearing material in contact with said plasma of the etching gas.

Claim 11

Dependent Claim 98 words

A process for selectively etching a mass, comprising: providing an etching mask over the mass to expose an area of the mass to be etched; and providing a plasma of an etching gas in contact with said mass in an etching chamber, said etching gas containing hydrogen bromide, bromine or a combination thereof as a main reactive component that reacts with said mass, said etching gas not containing a carbon-bearing component, whereby said exposed area of said mass is selectivity etched, wherein said etching chamber has no carbon-bearing material in contact with said plasma of the etching gas.

Claim 12

Dependent Claim 29 words

A process according to claim 8 or 9, wherein said etching gas contains less than 120 ppm of carbon content based on the total weight of said etching gas.

Claim 13

Dependent Claim 27 words

A process according to claim 10, wherein said etching gas contains less than 40 ppm of carbon content based on the total weight of said etching gas.

Claim 14

Dependent Claim 21 words

A process according to any one of claims 8 to 11, wherein said etching mask is composed of a non-carbon-containing material.

Claim 15

Dependent Claim 31 words

A process according to any one of claims 8 to 12, wherein said mass is made of a polycrystalline silicon and said etching mask is made of silicon oxide or nitride.

Claim 16

Dependent Claim 52 words

A process according to any preceding claim, wherein said etching gas contains hydrogen bromide as a main reactive component that reacts with said mass, and wherein there is provided around said mass having said etching mask of the organic material thereover an atmosphere containing excited oxygen atoms separated from a plasma thereof.

Claim 17

Dependent Claim 92 words

A process for selectively etching a mass, comprising: providing an etching mask of an organic material over the mass to expose an area of the mass to be etched; providing a plasma of an etching gas in contact with said mass, said etching gas containing hydrogen bromide as a main reactive component that reacts with said mass, whereby said exposed area of said mass is selectively etched; and providing around said mass having said etching mask of the organic material thereover, an atmosphere containing excited oxygen atoms separated from a plasma thereof.

Claim 18

Dependent Claim 92 words

A process for selectively etching a mass, comprising: providing an etching mask of an organic material over the mass to expose an area of the mass to be etched; providing a plasma of an etching gas in contact with said mass, said etching gas containing hydrogen bromide as a main reactive component that reacts with said mass, whereby said exposed area of said mass is selectively etched; and providing around said mass having said etching mask of the organic material thereover, an atmosphere containing excited oxygen atoms separated from a plasma thereof.

Claim 19

Dependent Claim 34 words

A process according to claim 15, further comprising the step of ashing said etching mask in a plasma of oxygen after said plasma etching step and before or after said excited oxygen atom treatment.

Claim 20

Dependent Claim 23 words

A process according to claim 14, 15, or 16, wherein said etching mask of an organic material is formed of an organic photoresist.

Claim 21

Dependent Claim 21 words

A process according to any one of claims 14 to 17, wherein said mass to be etched is of polycrystalline silicon.

Dry etching with hydrogen bromide or bromine

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